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Publication numberUS3932329 A
Publication typeGrant
Application numberUS 05/493,773
Publication dateJan 13, 1976
Filing dateAug 1, 1974
Priority dateAug 1, 1974
Publication number05493773, 493773, US 3932329 A, US 3932329A, US-A-3932329, US3932329 A, US3932329A
InventorsPallavoor R. Lakshmanan
Original AssigneeGulf Research & Development Company
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Adhesive composition
US 3932329 A
Abstract
An adhesive composition consisting essentially of a styrene-isoprene block copolymer, a zinc salt of rosin and a microcrystalline wax.
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Claims(7)
I claim:
1. An adhesive composition consisting essentially of a styrene-isoprene block copolymer, a zinc salt of rosin and a microcrystalline wax wherein the components are present in the following ranges:
Component        Weight Per Cent______________________________________Styrene-IsopreneBlock Copolymer  20-35Zinc Salt of Rosin            20-50Microcrystalline Wax             60-15.______________________________________
2. The composition of claim 1 wherein the components are present in the following ranges:
Component        Weight Per Cent______________________________________Styrene-Isoprene BlockCopolymer        15-40Zinc Salt of Rosin            15-50Microcrystalline Wax             70-10.______________________________________
3. The composition of claim 1 wherein the styrene-isoprene block copolymer has the following general configuration:
A -- B -- A
wherein A is a styrene polymer block having an average molecular weight of about 2,000 to about 100,000 and B is an isoprene polymer block having an average molecular weight of about 25,000 to about 1,000,000.
4. The composition of claim 3 wherein the styrene polymer block has an average molecular weight of about 5,000 to about 50,000 and the isoprene polymer block has an average molecular weight of about 50,000 to about 500,000.
5. The composition of claim 3 wherein the total of the terminal blocks A amount to about eight to about 50 weight per cent of the block copolymer.
6. The composition of claim 3 wherein the total of the terminal blocks A amount to about 10 to about 40 weight per cent of the block copolymer.
7. The composition of claim 1 wherein the zinc content of the zinc salt of rosin is from about four to about nine weight per cent.
Description

This invention relates to an adhesive composition having a bond strength at room temperature (about 72 F.) and above of at least about one pound per inch, preferably at least about 1.5 pounds per inch, consisting essentially of a styrene-isoprene block copolymer, a zinc salt or rosin (zinc resinate) and a microcrystalline wax.

The styrene-isoprene block copolymer product present in the adhesive composition of the present invention has the following general configuration:

A -- B -- A

wherein each terminal A is a styrene polymer block with a glass transition temperature above about room temperature (26 C.) and which is relatively incompatible with the elastomeric segment B, defined hereinafter, with the average molecular weight of each A being from about 2,000 to about 100,000, preferably from about 5,000 to about 50,000. The molecular weight of each segment A need not be the same. B is an isoprene polymer with a glass transition temperature below about room temperature (26 C.), with the average molecular weight of B being from about 25,000 to about 1,000,000, preferably from about 50,000 to about 500,000. The difference in glass transition temperature between an end block A, and a center block B, is preferably greater than about 100 C. In the block copolymer used herein the total of the terminal blocks A will amount to about eight to about 50 weight per cent, preferably about 10 to about 40 weight per cent, based on the total weight of the block copolymer.

The second component of the adhesive herein is a zinc salt of rosin (including a disproportionated rosin) having a zinc content of between about four and about nine weight per cent and a melting point (Ring and Ball softening points) of between about 80 to about 190 C. Rosin disproportionation involves, for example, heating the resin in excess of 200 C. to convert the oxidation-susceptible sites, e.g., conjugated double bond in the abietic acid structure, to less susceptible structures, such as dehydro-abietic acid, tetrahydro-abietic acid and dihydro-abietic acid.

The third component of the claimed adhesive is a microcrystalline wax. By "microcrystalline wax", I intend to include branched-chain hydrocarbons and alkylcycloaliphatic (naphthenic hydrocarbons) as well as straight-chain hydrocarbons whose molecular weight range is from about 400 to about 800, as defined, for example, in Encyclopedia of Polymer Science and Technology, Interscience Publishers-A division of John Wiley, New York, New York -- 1971 -- Volume 14, pages 770 and 771.

The adhesive composition herein will consist essentially of the following components:

               Weight Per Cent            Broad       PreferredComponent        Range       Range______________________________________Styrene-Isoprene 15-40       20-35Block CopolymerZinc Salt        15-50       20-50of RosinMicrocrystalline 70-10       60-15Wax______________________________________

If desired, an antioxidant, such as 1,3,5-trimethyl-2,4,6-(3,5-ditertiarybutyl-4-hydroxybenzyl)benzene or dilaurylthiopropionate, can also be incorporated in the adhesive composition in an amount of about 0.1 to about five, preferably about 0.2 to about two, weight per cent, based on the weight of the final composition.

The adhesive composition can be prepared in any conventional manner. Thus, for example, a preferred procedure involves the use of the so-called melt-mixing technique wherein the microcrystalline wax, together with antioxidant, if used, is maintained in a stirred, molten state at a temperature of about 100 to about 190 C., preferably about 130 to about 170 C., during which time the zinc salt of rosin is added thereto, followed by the styreneisoprene block copolymer. Mixing is continued until a homogeneous mixture is obtained.

The new adhesives of the present invention can be used as a hot melt adhesive to bond a plastic film, such as polyethylene, to itself or to paper, cardboard, aluminum foil, etc. In particular the new adhesives can be used to bond polyethylene to itself. A particularly preferred utility resides in bonding polyethylene to itself in the preparation of polyethylene grocery bags that are often used in place of Kraft paper grocery bags. In making such bags that would be competitive with those made of Kraft paper it is desirable that polyethylene bags have a bond strength at room temperature (about 72 F.) and above of at least about one pound per inch, preferably at least about 1.5 pounds per inch.

The improved adhesive compositions of the present invention can be understood by reference to the following. Compositions were prepared following the melt-mixing technique described, using a temperature of 160 to 170 C., containing (1) Kraton 1107; (2) Sta-tac 100, Staybelite Ester 10 or Zirex; (3) Microwax 15, Multiwax 180M or Gulfwax 40; and (4) the antioxidants 1,3,5-trimethyl-2,4,6-(3,5-ditertiary-4-hydroxybenzyl)benzene and dilaurylthiodi-propionate.

Polyethylene laminate test specimens were prepared by applying each of the adhesives so prepared to a 2.0 mil (3 inch 10 inch) high density polyethylene film by means of an electrically-operated glue gun that dispensed molten adhesive either by mechanical or manual means. The adhesive was applied at 149 to 154 C. to the film as a continuous bead 1/8 inch wide and then a film of similar dimension was placed on top of the film carrying the bead of adhesive. The laminates were permitted to rest for 48 hours prior to test specimen preparations. Three specimens, each 1 inch 3 inches, were then cut from the film samples in a direction across the adhesive direction. The bond strength was measured by peeling at the glue line by means of a suitable test device, such as an Instron test device, at a peel rate of 2 inches per minute. The maximum strength in pounds necessary to cause rupture of the bond was noted. The average of three such determinations was recorded. The results obtained are tabulated below in Table I.

                                  Table I__________________________________________________________________________Run Number     1  2  3  4  5  6  7  8  9   10   11   12    13  14__________________________________________________________________________Components,GramsKraton 1107     20 20 20 20 20 20 20 20 20  20   20   24    20  24Sta-tac 100     20 30 None              None                 None                    None                       None                          None                             None                                 None None None  None                                                     30Staybelite  Ester 10     None        None           20 26 30 None                       None                          None                             None                                 None None None  None                                                     NoneZirex     None        None           None              None                 None                    20 26 30 20  26   30   30    26  NoneMicrowax 15     60 60 60 54 50 60 54 50 None                                 None None None  None                                                     NoneMultiwax 180M     None        None           None              None                 None                    None                       None                          None                             60  54   50   46    None                                                     46Gulfwax 40     None        None           None              None                 None                    None                       None                          None                             None                                 None None None  54  None1,3,5-tri-methyl-2,4,6-(3,5-ditertiary-4-hydroxybenzyl)benzene     0.5        0.5           0.5              0.5                 0.5                    0.5                       0.5                          0.5                             0.5 0.5  0.5  0.5   0.5 0.5Dilaurylthio-  dipropionate     0.5        0.5           0.5              0.5                 0.5                    0.5                       0.5                          0.5                             0.5 0.5  0.5  0.5   0.5 0.5ResultsRing and BallSofteningPoint, F.      194         198           196              196                 192                     192                        200                           196                             207 207  208  212   188 200Viscosity,Cps at 300F.     1875        2000           475              590                 700                    1500                       1750                          1910                             11,400                                 11,200                                      11,200                                           >25,000                                                 886 10,500Bond Strength,Pounds/Inch At  120F.     0.7        0.9           0.5              0.4                 0.5                    1.1                       2.8                          2.1                             1.3 1.6  1.9  2.5   0.8 0.6   73F.     6.4*        6.2*           6.5              6.7                 7.3                    5.3*                       6.1*                          6.3*                             7.5 6.4  6.6  7.2   6.8 6.7*__________________________________________________________________________ * Film tore at indicated bond strength

Referring to the components used in the adhesive compositions above, Kraton 1107 is a styrene-isoprene block copolymer made and sold by Shell Chemicals wherein the terminal styrene block has a molecular weight of about 2,000 to about 100,000 and the center isoprene block has a molecular weight of about 25,000 to about 1,000,000, with the styrene block constituting about 15 per cent by weight of the total block: Sta-tac 100 is an isoprenepiperylene copolymer made and sold by Rheichold Chemicals, Inc., having a melting point of 105 C.; Staybelite Ester 10 is a glycerol ester of hydrogenated rosin made and sold by Hercules, Inc.; Zirex is a zinc resinate containing 8.75 weight per cent zinc having a melting point of 158 to 164 C. and is made and sold by Rheichold Chemicals, Inc.; Multiwax 180M is a microcrystalline wax having a melting point (ASTM D-127) of 180 to 190 F., a needle penetration (ASTM D-1321) at 77 F. of 15 to 20 and a Saybolt Viscosity (ASTM D-88) at 210 F. SUS of 75 to 90 and is made and sold by Sonneborn Division of Witco Chemicals Company; Microwax 15 is a microcrystalline wax having a melting point (ASTM D-127) of 187 F. and is made and sold by International Wax Refining Company; and Gulfwax 40 has a melting point (ASTM D-87) of 140.1 F., a needle penetration (ASTM D-1321) at 77 F. of 14 and a Saybolt Viscosity (ASTM D-127) at 210 F. SUS of 41.6 and is made and sold by Gulf Oil Corporation.

The data in Table I illustrates the uniqueness of the adhesive composition defined and claimed herein in providing a bond strength that is adequate at room temperature and above. The compositions of Examples 1 and 2, containing a styrene-isoprene block copolymer, an isoprene-piperylene copolymer and microcrystalline wax, and of Examples 3, 4 and 5, containing a styrene-isoprene block copolymer, a glycerol ester of a hydrogenated rosin and microcrystalline wax, showed unacceptable bonding strength at 73 F. However, in each of Examples 6, 7 and 8, the mere substitution of the zinc salt of rosin (zinc resinate) for either the isoprenepiperylene copolymer or the glycerol ester of a hydrogenated rosin resulted in adhesive compositions having superior bonding strengths. This is further illustrated in Examples 9, 10, 11 and 12 which are similar to Examples 6, 7 and 8 except that a different microcrystalline wax was used. Example 13 shows that even though a styreneisoprene block copolymer and a zinc salt of rosin are present in an adhesive composition the additional presence of a microcrystalline wax is critical. In this Example a paraffin wax was substituted for the microcrystalline wax but the composition failed to have an adequate bonding strength at 120 F. Similarly, the absence of a zinc salt of rosin is shown to be critical in Example 14. Even though the styrene-isoprene block copolymer and a microcrystalline wax are present, the zinc salt of rosin is replaced with an isoprenepiperylene copolymer. It will be noted that the bonding strength of the adhesive composition at 120 F. is unsatisfactory.

Obviously, many modifications and variations of the invention, as hereinabove set forth, can be made without departing from the spirit and scope thereof and, therefore, only such limitations should be imposed as are indicated in the appended claims.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US3198760 *Aug 15, 1961Aug 3, 1965Tenneco ChemPolychloroprene stabilized with a phenol-terpene resin and a metal resinate and process for preparation
US3231635 *Oct 7, 1963Jan 25, 1966Shell Oil CoProcess for the preparation of block copolymers
US3658740 *Dec 5, 1969Apr 25, 1972Phillips Petroleum CoPressure sensitive adhesives
Non-Patent Citations
Reference
1"Railsback" Rubber Age, Jan. 1964, p. 584.
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4301050 *Jun 9, 1980Nov 17, 1981Atom Chemical Paint Co., Ltd.Road marking composition
US5026753 *Feb 22, 1989Jun 25, 1991Union Camp CorporationResinous binders comprising a metal rosin resinate and a carboxylated polystyrene resin
US5026754 *Apr 18, 1989Jun 25, 1991Union Camp CorporationResinous binders comprising a metal rosin resinate and a pendant tertiary amine polymer
US5149741 *Sep 20, 1991Sep 22, 1992Findley Adhesives, Inc.Hot melt construction adhesives for disposable soft goods
US5266394 *Aug 4, 1992Nov 30, 1993The Dow Chemical CompanyDisposable articles of manufacture containing polystyrene-polyisoprene-polystyrene block copolymers
US7683114Mar 12, 2007Mar 23, 2010Henkel Ag & Co. KgaaLow application temperature hot melt adhesive
US7795336Oct 18, 2002Sep 14, 2010Henkel Ag & Co. KgaaLow application temperature hot melt adhesive
US7795341Feb 6, 2004Sep 14, 2010Henkel Ag & Co. KgaaIonomer-containing hot melt adhesive
US7799863Jan 31, 2005Sep 21, 2010Henkel Ag & Co. KgaaLow application temperature elastic attachment adhesive
US8969456Jun 9, 2010Mar 3, 20153M Innovative Properties CompanyMethod of making a hot melt pressure-sensitive adhesive
US20040077240 *Oct 18, 2002Apr 22, 2004Paul Charles W.Low application temperature hot melt adhesive
US20040131846 *Dec 11, 2003Jul 8, 2004Epple Thomas C.Microsphere containing electron beam cured pressure-sensitive adhesive tapes and methods of making and using same
US20050176867 *Feb 6, 2004Aug 11, 2005Qiwei HeLow application temperature elastic attachment adhesive
US20050176868 *Feb 6, 2004Aug 11, 2005Qiwei HeIonomer-containing hot melt adhesive
US20070161742 *Jan 31, 2005Jul 12, 2007Qiwei HeLow application temperature elastic attachment adhesive
US20070173153 *Mar 12, 2007Jul 26, 2007Paul Charles WLow application temperature hot melt adhesive
EP0067559A1 *May 21, 1982Dec 22, 1982Minnesota Mining And Manufacturing CompanyShear-activated innerseal
EP1736067A1Jul 22, 2002Dec 27, 2006Guangdong Esquel Textiles Co., Ltd.Wrinkle free garment and method of manufacture
WO2004035705A2Oct 20, 2003Apr 29, 2004National Starch And Chemical Investment Holding CorporationLow application temperature hot melt adhesive
WO2004035705A3 *Oct 20, 2003Jun 10, 2004Nat Starch Chem InvestLow application temperature hot melt adhesive
WO2005078033A1 *Jan 31, 2005Aug 25, 2005National Starch And Chemical Investment Holding CorporationLow application temperature elastic adhesive
Classifications
U.S. Classification524/274, 524/571
International ClassificationC09J193/04, C09J191/06, C09J153/02
Cooperative ClassificationC09J153/02, C09J193/04, C09J191/06
European ClassificationC09J153/02, C09J191/06, C09J193/04
Legal Events
DateCodeEventDescription
Feb 10, 1986ASAssignment
Owner name: BAYCHEM INTERNATIONAL, INC., SUITE 116, CHAMPIONS
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:GULF OIL CORPORATION, A CORP. OF PA.;REEL/FRAME:004513/0911
Effective date: 19840329